The low power consumption and high efficiency levels of LEDs versus traditional automotive lighting such as Xenon and halogen are proving desirable to automotive engineers tasked with reducing CO2 emissions and achieving energy savings from all areas of the vehicle.
Front lighting applications that include high-beam, low-beam, daytime running lights (DRLs), and position lights are a particular area where significant energy savings and efficiency gains can be achieved by adopting LEDs—efficiencies that can be translated directly into fuel consumption savings. This is in addition to the important benefits of long operational life, design freedom, and greater functionality that LED-based modules offer versus established approaches.
Being able to successfully develop and implement cost-effective, high efficiency lamp modules that contain strings of high brightness (HB) LEDs is dependent on the design of ECUs that utilise equally efficient system on chip (SoC) solutions that integrate all necessary front lighting specific features including diagnostics and connectivity.
First generation applications for LEDs in front lighting saw them being used as DRLs. Despite only having a low light output and therefore low power consumption, the fact that by definition DRLs are always on when the vehicle engine is running means additional fuel is being used all the time. LED-based DRLs consume in the region of just 9W helping to keep this additional fuel consumption to an absolute minimum. The potential exists for HB LEDs to satisfy all existing front lighting applications that comprise high beam, low beam, DRLs, turn indicators, and fog lights, as well as to provide an optimum solution to new and emerging functions such as beam shaping and motorway spotlighting.
On this evolution path to 100% LED front lighting modules, some vehicle manufacturers are currently selecting only the functions that yield the greatest benefits in terms of energy saving for early conversion to LEDs. The aforementioned DRLs, that are gradually becoming a legal requirement in more countries, are one example. Another is the decision to retain the use of halogen for high beam for the time being—the thought process behind this is that as high beam is used for such a small amount of time (only at night and then only when there are no vehicles approaching from the opposite direction), then total power/fuel savings would be minimal.
As the cost of HB LEDs decreases and their overall performance increases, the trend for new vehicle designs to adopt them will accelerate. This will be further driven by the robust, high efficiency (in the region of 90%) SoC LED drivers such as ON Semiconductor's NCV786XX series that provide a significant step forward compared to switched mode regulators for supporting the medium to high total power requirements of front lighting.
Read this complete article here, which details system-level challenges of incorporating front-lighting LEDs, including temperature and EMI concerns, beam shaping, and current regulation, courtesy of Automotive Designline Europe.
The automotive environment requires ambient temperature operation up to 85deg.C and significant vibration. Also high intensity LED's might be rated at 20,000 hours, but at that time the intensity will have dropped to 50%. Also I have seen rear lamp LED's where 1 or more LED's have failed (probably due to mechanical vibration) which for a headlight would be unacceptable. I believe early adopters of LED Headlights will be very disappointed due to these factors.
Paul, I followed to link for complete article. In that you refer to NCV78663. I tried to get PDF datasheet for it on ON Semi web pages, but could not locate it.
Will you please send me link or PDF data sheet for NCV78663 at email@example.com.
LED Lighting in automobile is highly desirable. As this technology will soon become essential, there is need to have some inernational standard. This stanadard will have many advantages. First, the input power, communication and control, form factor, connection and electro-optical properties will be same or well defined for all LED lamps. With this, automobile manufacturer and end user will have freedom to replace one LED Lamp with another, just like normal lamp. LED driver technology is still evoloving and we will see very high quality, better intelligence, more powerful light source (e.g. introduction of Cree X-Lamp MPL LED). With introduction of standard, end user can upgrade their LED lighting in car for few more years and take advantage of new technology. LED an LED driver vendors can exploit this opportunity of dynamic market.
Does any international body in automobile industry put effrot for this cause?
LED head lights need to work at high temperatures near the engine. The design needs to take care of the ambience very much. The system on chip LED drivers can monitor and control the various factors described in this article.